This invention relates generally to electrical testing devices and more specifically to conductor identification devices.
Identifying one circuit out of a multiple group is a difficult and time consuming task even when both ends of the entire group are located on a work bench in front of you, but the task is severely aggravated when the circuits are enclosed in the walls of a building and the terminals spread out among the floors and rooms of that building. The choice of approaches in such a case has been limited to using several workers and shouting back and forth between them, or for one worker to move back and forth between terminals as he works by trial and error. Anyone who has ever attempted to find the fuse by which to disconnect an outlet in his home knows the usual process. First, one turns on a light connected to that outlet. Then you run to the main distribution box, usually down one or two flights of stairs, and taking your best guess as to which circuit the outlet is on, remove that fuse. Then you go back to the lamp and verify whether it is on or off. If it is off, the guess was correct; if not, one has to try again. Multiplying this procedure by the number of electrical outlets in a building makes the tracing of power circuits a tedious and costly procedure. The prior art of circuit tracing deals essentially with tracing for signal, telephone and computer circuits, using complex and sophisticated devices in which all terminals are connected to one device which identifies the various lines. The typical electrician can not carry such equipment with him, and, even if he could, it is impossible to connect such a device to all the building outlets at one time.
The present invention gives to the typical building trades electrician an inexpensive portable device by which he can trace the circuits within a building with a minimum of labor.